#include <highgui.h>
#include <cv.h>
#include <iostream>

using namespace std;
using namespace cv;

// imgproc.hpp
//GC_BGD    = 0,  //!< background
//GC_FGD    = 1,  //!< foreground
//GC_PR_BGD = 2,  //!< most probably background
//GC_PR_FGD = 3   //!< most probably foreground 

const Scalar RED = Scalar(0,0,255);
const Scalar PINK = Scalar(230,130,255);
const Scalar BLUE = Scalar(255,0,0);
const Scalar LIGHTBLUE = Scalar(255,255,160);
const Scalar GREEN = Scalar(0,255,0);

const int BGD_KEY = CV_EVENT_FLAG_CTRLKEY;
const int FGD_KEY = CV_EVENT_FLAG_SHIFTKEY;

void getBinMask( const Mat& comMask, Mat& binMask )
{
  if( comMask.empty() || comMask.type()!=CV_8UC1 )
    CV_Error( CV_StsBadArg, "comMask is empty or has incorrect type (not CV_8UC1)" );
  if( binMask.empty() || binMask.rows!=comMask.rows || binMask.cols!=comMask.cols )
    binMask.create( comMask.size(), CV_8UC1 );
  binMask = comMask & 1; // 1(GC_FGD) or 3(GC_PR_FGD)
}

class GCApplication
{
public:
  enum { NOT_SET = 0, IN_PROCESS = 1, SET = 2 };
  static const int radius = 2;
  static const int thickness = -1;

  void reset();
  void setImageAndWinName(const Mat& _image, const string& _winName);
  void showImage() const;
  void mouseClick(int event, int x, int y, int flags, void* param);
  int nextIter();
  int getIterCount() const { return iterCount; }
private:
  void setRectInMask();
  void setLblsInMask( int flags, Point p, bool isPr );

  const string* winName;
  const Mat* image;
  Mat mask;
  Mat bgdModel, fgdModel;

  uchar rectState, lblsState, prLblsState;
  bool isInitialized;

  Rect rect;
  vector<Point> fgdPxls, bgdPxls, prFgdPxls, prBgdPxls;
  int iterCount;
};

void GCApplication::reset()
{
  if( !mask.empty() )
    mask.setTo(Scalar::all(GC_BGD));

  bgdPxls.clear(); 
  fgdPxls.clear();
  prBgdPxls.clear();  
  prFgdPxls.clear();

  isInitialized = false;
  rectState = NOT_SET;
  lblsState = NOT_SET;
  prLblsState = NOT_SET;
  iterCount = 0;
}

void GCApplication::setImageAndWinName( const Mat& _image, const string& _winName  )
{
  if( _image.empty() || _winName.empty() )
    return;
  image = &_image;
  winName = &_winName;
  mask.create(image->size(), CV_8UC1);
  reset();
}

void GCApplication::showImage() const
{
  if(image->empty() || winName->empty())
    return;

  Mat res;
  Mat binMask;

  if(!isInitialized) {
    image->copyTo( res );

  } else {
    getBinMask(mask, binMask);
    image->copyTo(res, binMask);
  }

  // () draw a rectangle and foreground, background pixels
  vector<Point>::const_iterator it;
  for( it = bgdPxls.begin(); it != bgdPxls.end(); ++it )
    circle( res, *it, radius, BLUE, thickness );
  for( it = fgdPxls.begin(); it != fgdPxls.end(); ++it )
    circle( res, *it, radius, RED, thickness );
  for( it = prBgdPxls.begin(); it != prBgdPxls.end(); ++it )
    circle( res, *it, radius, LIGHTBLUE, thickness );
  for( it = prFgdPxls.begin(); it != prFgdPxls.end(); ++it )
    circle( res, *it, radius, PINK, thickness );

  if( rectState == IN_PROCESS || rectState == SET )
    rectangle( res, Point( rect.x, rect.y ), Point(rect.x + rect.width, rect.y + rect.height ), GREEN, 2);

  imshow( *winName, res );
}

void GCApplication::setRectInMask()
{
  // rect->GC_PR_FGD, rest->GC_BGD
  assert( !mask.empty() );
  mask.setTo( GC_BGD );
  rect.x = max(0, rect.x);
  rect.y = max(0, rect.y);
  rect.width = min(rect.width, image->cols-rect.x);
  rect.height = min(rect.height, image->rows-rect.y);
  (mask(rect)).setTo( Scalar(GC_PR_FGD) );
}

void GCApplication::setLblsInMask(int flags, Point p, bool isPr)
{
  vector<Point> *bpxls, *fpxls;
  uchar bvalue, fvalue;

  // is Probabilistic ?
  if(!isPr) {
    bpxls = &bgdPxls;
    fpxls = &fgdPxls;
    bvalue = GC_BGD;
    fvalue = GC_FGD;

  } else {
    bpxls = &prBgdPxls;
    fpxls = &prFgdPxls;
    bvalue = GC_PR_BGD;
    fvalue = GC_PR_FGD;
  }

  if(flags & BGD_KEY) {
    bpxls->push_back(p);
    circle( mask, p, radius, bvalue, thickness );
  }

  if(flags & FGD_KEY) {
    fpxls->push_back(p);
    circle( mask, p, radius, fvalue, thickness );
  }
}

void GCApplication::mouseClick( int event, int x, int y, int flags, void* param )
{
  switch(event) {

    case CV_EVENT_LBUTTONDOWN: 
      {
        bool isb = (flags & BGD_KEY) != 0,
          isf = (flags & FGD_KEY) != 0;
        if(rectState == NOT_SET && !isb && !isf) {
          rectState = IN_PROCESS;
          rect = Rect( x, y, 1, 1 );
        }
        if ((isb || isf) && rectState == SET)
          lblsState = IN_PROCESS;
      }
      break;
    
    case CV_EVENT_RBUTTONDOWN:
      {
        bool isb = (flags & BGD_KEY) != 0,
          isf = (flags & FGD_KEY) != 0;
        if ( (isb || isf) && rectState == SET )
          prLblsState = IN_PROCESS;
      }
      break;

    // set rect or GC_BGD(GC_FGD) labels
    case CV_EVENT_LBUTTONUP:
      if(rectState == IN_PROCESS) {
        rect = Rect( Point(rect.x, rect.y), Point(x,y) );
        rectState = SET;
        setRectInMask();
        assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
        showImage();
      }
      if(lblsState == IN_PROCESS) {
        setLblsInMask(flags, Point(x,y), false);
        lblsState = SET;
        showImage();
      }
      break;

    // set GC_PR_BGD(GC_PR_FGD) labels
    case CV_EVENT_RBUTTONUP:
      if(prLblsState == IN_PROCESS) {
        setLblsInMask(flags, Point(x,y), true);
        prLblsState = SET;
        showImage();
      }
      break;

    // set rect or GC_BGD(GC_FGD), GC_PR_BGD(GC_PR_FGD) labels continuously
    case CV_EVENT_MOUSEMOVE:
      if(rectState == IN_PROCESS) {
        rect = Rect( Point(rect.x, rect.y), Point(x,y) );
        assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
        showImage();
      }
      else if(lblsState == IN_PROCESS) {
        setLblsInMask(flags, Point(x,y), false);
        showImage();
      }
      else if(prLblsState == IN_PROCESS) {
        setLblsInMask(flags, Point(x,y), true);
        showImage();
      }
      break;
    }
}

int GCApplication::nextIter()
{
  if(isInitialized) {
    grabCut( *image, mask, rect, bgdModel, fgdModel, 1 );
  } else {
    if(rectState != SET) return iterCount;
    grabCut( *image, mask, rect, bgdModel, fgdModel, 1, GC_INIT_WITH_MASK );
    isInitialized = true;
  }
  iterCount++;

  bgdPxls.clear(); 
  fgdPxls.clear();
  prBgdPxls.clear(); 
  prFgdPxls.clear();

  return iterCount;
}

GCApplication gcapp;

void on_mouse( int event, int x, int y, int flags, void* param )
{
  gcapp.mouseClick( event, x, y, flags, param );
}

int main( int argc, char** argv )
{
  const string filename = argc > 1 ? argv[1] : "../image/white_flower.png";
  Mat image = imread(filename, 1);
  if(image.empty())
    return 1;

  cout << "First, select the rectangular area\n" <<
    "Hot keys: \n"
    "\tESC - quit the program\n"
    "\tr - restore the original image\n"
    "\tn - next iteration\n"
    "\n"
    "\tleft mouse button - set rectangle\n"
    "\n"
    "\tCTRL+left mouse button - set GC_BGD pixels\n"
    "\tSHIFT+left mouse button - set CG_FGD pixels\n"
    "\n"
    "\tCTRL+right mouse button - set GC_PR_BGD pixels\n"
    "\tSHIFT+right mouse button - set CG_PR_FGD pixels\n";
  
  const string winName = "image";
  namedWindow(winName.c_str(), CV_WINDOW_AUTOSIZE);
  cvSetMouseCallback(winName.c_str(), on_mouse, 0);

  gcapp.setImageAndWinName(image, winName);
  gcapp.showImage();

  while(1) {
    int c = waitKey(0);
    switch((char)c) {

    // () exit
    case '\x1b':
      return 0;

    // () reset
    case 'r':
      cout << endl;
      gcapp.reset();
      gcapp.showImage();
      break;

     // () iteration
    case 'n':
      int iterCount = gcapp.getIterCount();
      cout << "<" << iterCount << "... ";
      int newIterCount = gcapp.nextIter();
      if( newIterCount > iterCount ) {
        gcapp.showImage();
        cout << iterCount << ">" << endl;
      }
      else
        cout << "rect must be determined>" << endl;
      break;
    }
  }

  return 0;
}
